Extending a logical volume in a virtual machine running Red Hat or Cent OS

- Power off the virtual machine.
- Edit the virtual machine settings and extend the virtual disk size. For more information, see Increasing the size of a virtual disk (1004047).
- Power on the virtual machine.
- Identify the device name, which is by default /dev/sda, and confirm the new size by running the command:

# fdisk -l

- Create a new primary partition:
Run the command:

# fdisk /dev/sda (depending the results of the step 4)
Press p to print the partition table to identify the number of partitions. By default, there are 2: sda1 and sda2.
Press n to create a new primary partition.
Press p for primary.
Press 3 for the partition number, depending on the output of the partition table print.
Press Enter two times.
Press t to change the system's partition ID.
Press 3 to select the newly creation partition.
Type 8e to change the Hex Code of the partition for Linux LVM.
Press w to write the changes to the partition table.

- Restart the virtual machine.
- Run this command to verify that the changes were saved to the partition table and that the new partition has an 8e type:

# fdisk -l

- Run this command to convert the new partition to a physical volume:

Note: The number for the sda can change depending on system setup. Use the sda number that was created in step 5.

# pvcreate /dev/sda3

- Run this command to extend the physical volume:

# vgextend VolGroup00 /dev/sda3

Note: To determine which volume group to extend, use the command vgdisplay.

- Run this command to verify how many physical extents are available to the Volume Group:

# vgdisplay VolGroup00 | grep "Free"

- Run the following command to extend the Logical Volume:

# lvextend -L+#G /dev/VolGroup00/LogVol00

Where # is the number of Free space in GB available as per the previous command. Use the full number output from Step 10 including any decimals.

Note: To determine which logical volume to extend, use the command lvdisplay.

- Run the following command to expand the ext3 filesystem online, inside of the Logical Volume:

# ext2online /dev/VolGroup00/LogVol00

- Notes:
Use resize2fs instead of ext2online if it is not a Red Hat virtual machine.
By default, Red Hat and CentOS 7 use the XFS file system you can grow the file system by running the xfs_growfs command.

Run the following command to verify that the / filesystem has the new space available:

# df -h /
- Related Information

Note: If the extended vmdk does not reflect the new size under Linux guest OS, rescan SCSI device using the following command:

echo 1 > /sys/block/$DEVICE/device/rescan where $DEVICE is 'sda'

For example:

echo 1 > /sys/block/sda/device/rescan